Abstract: To explore the inhibitory effects of different polar extracts of acorns on α-amylase and α-glucosidase. 40% ethanol and cellulase were combined for extraction,followed by extraction and separation with petroleum ether and ethyl acetate to obtain crude acorn extract,petroleum ether phase,ethyl acetate phase and raffinate water phase.The in vitro hypoglycemic activity of each polar component was studied by measuring enzyme inhibition,and the possible active components of each extract were verified by high performance liquid chromatography (HPLC) and molecular docking assay.The results showed that the all extracts of different polarities of acorn had obvious inhibitory effects on α-amylase and α-glucosidase,and the ethyl acetate phase had the best inhibitory effect( IC50=1.590±0.073 mg/g and 3.927±0.019 (×10-3 mg/g),respectively).It was found by the HPLC content assay that the content of 6 active ingredients in the ethyl acetate phase was the highest,and the content of ellagic acid was 500.75±6.93 mg/g,which was 10-50 times higher than that of other components.Molecular docking results showed that only ellagic acid had good binding activity with α-amylase and α-glucosidase.The above results indicate that ellagic acid may be the main active component of acorn ethyl acetate extract to inhibit α-amylase and α-glucosidase.

Key words: acorn, polar extract, α-amylase, α-glucosidase, HPLC